Constitutive modelling of fibre-reinforced composites with unidirectional plies using a plasticity-based approach

Abstract

Please cite this article as: Vyas, G.M., Pinho, S.T., Robinson, P., Constitutive modelling of fibre-reinforced composites with unidirectional plies using a plasticity-based approach, Composites Science and Technology (2011), doi: 10.1016/j.compscitech.2011 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.Constitutive modelling of fibre-reinforced composites with unidirectional plies using a plasticity-based approach AbstractThis paper presents the development of a constitutive model able to accurately represent the full non-linear mechanical response of polymer-matrix fibre-reinforced composites with unidirectional (UD) plies under quasi-static loading. This is achieved by utilising an elasto-plastic modelling framework. The model captures key features that are often neglected in constitutive modelling of UD composites, such as the effect of hydrostatic pressure on both the elastic and non-elastic material response, the effect of multiaxial loading and dependence of the yield stress on the applied pressure.The constitutive model includes a novel yield function which accurately represents the yielding of the matrix within a unidirectional fibre-reinforced composite by removing the dependence on the stress in the fibre direction. A non-associative flow rule is used to capture the pressure sensitivity of the material. The experimentally observed translation of subsequent yield surfaces is modelled using a non-linear kinematic hardening rule. Furthermore, evolution laws are proposed for the non-linear hardening that relate to the applied hydrostatic pressure. * Corresponding author Email address: gv04@imperial.ac.uk (G.M. Vyas) Preprint submitted to ElsevierMultiaxial test data is used to show that the model is able to predict the nonlinear response under complex loading combinations, given only the experimental response from two uniaxial tests.

Mechanisms for Kink Band Evolution in Polymer Matrix Composites: A Digital Image Correlation and Finite Element Study

“…[59]. Several reports in the literature use a viscoelastic approach to capture the time dependent behavior of these materials [57,58].…”

“…A pressure dependent yield criterion for UD composites is formulated and achieved by some mathematical manipulations in an existing yield criterion. The proposed yield criterion by Vyasa [59] is both hydrostatically sensitive (predicts the increase in yield with pressure) and accounts for the different response of UD composites in the fiber direction.…”

“…Several reports in the literature use a viscoelastic approach to capture the time dependent behavior of these materials [57,58]. Vyasa [59] studied loading under quasi-static conditions at the ply level and so an elastic-plastic constitutive law is used with a Drucker-Prager yield criterion. A pressure dependent yield criterion for UD composites is formulated and achieved by some mathematical manipulations in an existing yield criterion.…”

Modelling the nonlinear behaviour and fracture process of AS4/PEKK thermoplastic composite under shear loading

“…This model was coupled with a smeared crack model to simulate the onset and propagation of ply failure. Vyas et al [40] presented a plasticity-based approach to model the nonlinear mechanical response of polymer-matrix fibre-reinforced composites with unidirectional plies under quasi-static loading. However, the interactive damage mechanisms and material non-linearity with degraded shear moduli are not handled well by these models.…”

Modelling the crush behaviour of thermoplastic composites

“…Vogler [28] and Camanho [29] presented a fully three-dimensional transversely isotropic elastic-plastic constitutive model for composite materials to represent the plasticity-based non-linearities under multiaxial loading conditions. Vyas et al [30] presented a plasticity-based approach to model the nonlinear mechanical response of polymer-matrix fibre-reinforced composites with unidirectional plies under quasi-static loading. However, the interactive damage mechanisms and material nonlinearity with degraded shear moduli are not handled well by these models.…”